Method of encoding image information, its encoder, its decoding/composing method, its decoder/composer and recording medium on which those methods are recorded

ABSTRACT

When video signals are composed so that one video signal can be defined by (i) inputting plural video signals, (ii) attaching a picture identifier to the respective video signals for identifying the video signals, and (iii) composing some of the plural video signals, a picture coding method including the following processes is proposed. 1. Prepare composing information such as a composing sequence. 2. Encode at least the video signals having picture identifiers together with the composing information. A coding apparatus using this method, a picture decoding method that decodes the video signals coded with this method, a decoding apparatus using this decoding method are also proposed. A recording medium that records the data implementing the above methods is proposed.

DESCRIPTION

This Application is a U.S. National Phase Application of PCTInternational Application PCT/JP97/01975.

TECHNICAL FIELD

The present invention generally relates to coding and decoding videosignals, and more particularly to a method of coding plural pieces ofpicture information, an encoder using the method, a method of decodingand composing the coded plural digital picture data, an apparatus usingthis method, and a recording medium that has recorded these methods aswell as the data resulting from the execution of these methods.

PRIOR ART

Data compression (=encoding) is required for efficient storing andtransmitting of a digital picture.

Several method of encoding are available as prior art such as “discretecosine transform” (DCT) including JPEG and MPEG, and other wave-formencoding methods such as “sub-band”, “wavelet”, “fractal” and the like.Further, in order to remove redundant signals between pictures, aprediction method between pictures is employed, and then thedifferential signal is encoded by waveform encoding method.

Recently, a method of coding and decoding has been employed so that acoding efficiency can be improved as well as each object constituting apicture can be independently coded, transmitted, and decoded at areproduction side that composes the individual decoded object into apicture for displaying it.

An advantage of this method is that objects can be arbitrary combinedand composed thanks to an individual-object-coding method, wherebymoving pictures can be re-edited with ease. This method also can saverelatively unimportant objects from being reproduced depending onbusyness of the transmission lines, capacity of the reproductionapparatus, or taste of users without negative influence to viewing themotion pictures. In other words, object-wise scalability is possiblewith this method.

In order to embody the above function, the composing of individualobjects should be changed with ease. In the prior art, informationnecessary for composing objects is included in the coded data of eachobject. The information about composing objects includes the depth of anobject, placement thereof, and visibility thereof and the like. Whenre-editing is required or an object is required to be flexible such asbeing scaled down/up, the coded data must be analyzed first, and thenthe data relevant to the composing information is changed because thecomposing information is included in the coded data of the object.Further, the present invention aims to provide a recording medium thathas recorded the above methods and the data resulting from the executionof the above methods.

SUMMARY OF THE INVENTION

The present invention aims to provide a method of coding, a method ofdecoding and composing, as well as an apparatus using the same methods.With these methods and apparatus, composing information can be changedwith ease, when each object constituting a picture is independentlycoded and transmitted to a receiver which composes the plural pieces ofpicture information. More specifically, the present invention aims tochange the composing information with ease by saving the coded data frombeing analyzed.

A picture coding method of the present invention encodes video signalstogether with composing information through the following steps:

(1) input plural video signals;

(2) attach a picture identifier to the video signals individually foridentifying each video signal;

(3) when some of the plural video signals are to be composed into onesingle video signal, prepare relevant composing information such ascomposing sequence; and

(4) encode the video signals to which at least picture identifiers areattached and the composing information.

The present invention can provide a picture encoding apparatus thatemploys this method. The apparatus comprises the following elements:

(a) picture input means for inputting plural video signals;

(b) picture identifier attaching means for attaching a pictureidentifier to the plural video signals individually in order to identifyeach video signal;

(c) composing information preparation means for outputting the composinginformation in order to compose the plural video signals; and

(d) coding means for encoding the composing information and the videosignals having at least the picture identifiers.

Another coding method of the present invention encodes video signals andcomposing information through the following steps:

(1) divide one picture into plural objects in order to form pluralportions of the picture, whereby a single video signal is divided intoplural video portion signals;

(2) attach a picture identifier to the video portion signalsindividually for identifying each video portion signal;

(3) prepare composing information including composing sequence so thatthe video portion signals are composed into one single video signal; and

(4) encode the video portion signals having at least pictureidentifiers, and encode the composing information.

The present invention can also provide a picture coding apparatus thatemploys the above method. The apparatus comprises the following elementsso that one single video signal can be formed with plural pictures bycomposing:

(a) picture division means for dividing a video signal into plural videoportion signals;

(b) picture identifier attaching means for attaching a pictureidentifier to the video portion signals individually for identifyingeach video portion signal;

(c) composing information preparation means for outputting composinginformation in order to form a single video signal by composing theplural video portion signals; and

(d) coding means for encoding at least the composing information thevideo portion signals having the picture identifiers.

A decoding and composing method that can decode and compose the codedvideo signal undergone the above process comprises the following steps:

(1′) receive plural coded data;

(2′) decode the plural coded data;

(3′) extract the picture identifiers attached to the coded data.

On the other hand, the composing information is received, and pluralcoded data are decoded based on this information and the pictureidentifiers, then finally one decoded picture is obtained.

The present invention provides a picture decoding and composingapparatus that employs the above method and comprises the followingelements.

(a′) receiving means for receiving plural coded data;

(b′) decoding means for decoding the coded data received by thereceiving means;

(c′) picture identifier extraction means for extracting the pictureidentifiers attached to the coded data that are to be decoded by thedecoding means;

(d′) composing information receiving means for receiving the composinginformation that is utilized to compose the plural coded data; and,

(e′) composing means for composing the plural coded data based on atleast the picture identifiers and the composing information.

The composing information includes at least a composing sequence andpicture identifiers of the object pictures to be composed. According tothe composing sequence, a depth and location designated by the pictureidentifier of a portion picture are determined, whereby pluralreproduced portion pictures are composed. The picture decoding andcomposing apparatus further comprises input means, through which onlythe composing information independent of the coded data is modified, andthen the reproduced portion pictures are composed according to themodified composing information.

As described above, when elements, such as objects in a picture,defining the picture are coded and transmitted independently forcomposing each element into a picture, the composing information can bechanged with ease and can be flexibly as well as arbitrarily composed.Also when plural video portion signals are coded and transmitted forcomposing these plural signals into a new picture, the composinginformation can be changed readily and flexibly as well as arbitrarilycomposed. As a result, interactive performance is noticeably improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart depicting a method of coding plural video signalsin a first exemplary embodiment of the present invention.

FIG. 2 is a flowchart depicting a method of coding plural video signalsin a second exemplary embodiment of the present invention.

FIG. 3 illustrates structures of coded picture data and the picture datato be decoded. FIG. 3(A) illustrates first coded picture data. FIG. 3(B)shows multiplexed data of packetized first and second coded picturedata. FIG. 3(C) shows second coded picture data.

FIG. 4 depicts a content example of the composing information used inthe exemplary embodiment of the present invention.

FIG. 5 is a flowchart depicting a method of decoding the multiplexeddata of plural video signals utilized in a third exemplary embodiment.

FIG. 6 is a block diagram illustrating a decoding and composingapparatus utilized in the third exemplary embodiment of the presentinvention.

FIG. 7 is a schematic chart illustrating an example of composing pluralvideo signals, where each object is composed.

FIG. 8 is a timing chart of composing and displaying a picture, whichillustrates the decoding operation in the exemplary embodiment of thepresent invention.

FIG. 9 is a block diagram illustrating a decoding and composingapparatus utilized in a fourth exemplary embodiment of the presentinvention.

FIG. 10 illustrates a picture coding apparatus employing the methodshown in FIG. 1.

FIG. 11 illustrates a picture coding apparatus employing the methodshown in FIG. 2.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS Exemplary Embodiment 1

The first exemplary embodiment is described with reference to FIGS. 1, 3and 4. FIG. 1 is a flowchart depicting a method of coding plural videosignals in a first exemplary embodiment of the present invention. FIG. 3illustrates a bit-stream data-structure of the resultant digitally codedplural video signals. FIG. 4 shows a description example of the data.

In FIG. 1, input a plurality of video signals on Step 11. The pluralvideo signals will be detailed later with reference to FIGS. 3(A) and3(C). On Step 12, attach a picture identifier to each input video signalto be identified. In FIG. 3(A), an identifier (ID) 302 is attached topicture data 304 having time (i). In FIG. 3(C), an identifier (ID) 323is attached to picture data 328 having time (i).

On Step 13 in FIG. 1, output the composing information for forming acomposed video signal by composing plural video signals. FIG. 3(B)illustrates multiplexed data of packetized coded picture data shown inFIGS. 3(A) and 3(C). The composing information packet 319 is the onesupplied on Step 13.

On Step 14, encode the video signals at least having the pictureidentifier, and the composing information. The resultant coded videosignals are 304 and 330 to which identifiers (ID) 302 and 307 as well astime identifiers (TR) 303 and 329 are respectively attached. Anotherresultant coded video signal is 328 that has identifiers (ID) 323, 327and time identifier (TR) 324.

On Step 15 in FIG. 1, packetize and then transmit in multiplex the codedvideo signals shown in FIGS. 3(A) and 3(C). The packetized form is shownin FIG. 3(B). In this case, a packet 319 is independently provided forcontaining the composing information, while video packets 311 and 315are provided for the video signals. A composition parameter is describedin this packet 319 and transmitted, the parameter tells how to composeand output the video signals shown in FIGS. 3(A) and 3(C).

FIG. 4 shows an example of the above case, and composing information 401is depicted. A composition time 402 records the time when the videosignals are composed. A composition order (composing sequence) 403includes picture identifiers (OID), time identifiers (TR), depth (CO)and placement (XPOS, YPOS). Composing information for blending filter isrepresented with 404, a frame memory management is represented with 405.

In this case, a composing sequence is listed as part of composinginformation. When plural pictures to be composed differ in size, acoordinates converting parameter can be listed so that compositions richwith variety by changing the composing information can be achieved withease.

FIG. 10 includes the following elements: input terminal 211, pictureidentifier attaching means 212, composing information preparation means213, first encoding means 214 and second encoding means 215.

Operation of the picture coding apparatus of FIG. 10 is as follows:

-   -   (1) Input a plurality of video signals to input terminal 211        (Step 11 in FIG. 1)    -   (2) Attach a picture identifier to each input video signal for        identification in picture identifier attaching means 212 (Step        12 in FIG. 1)    -   (3) Send the input video signal with the picture identifiers to        composing information preparation means 213 via a line 216, and        output the composing information for forming a composed video        signal by composing a plurality of video signals (Step 13 in        FIG. 1)    -   (4) Send the video signals which at least have the picture        identifier and the composing information, to the first encoder        214 via a line 217, and encode the video signals with the        identifier (ID) as well as the time identifier (TR) by the first        encoder 214 (Step 14 in FIG. 1)    -   (5) Encode the composing information, passing through line 218,        with the first encoded video signals, passing through line 219,        by the second encoder 215 to form the transmitting signals (Step        15 in FIG. 1).

Exemplary Embodiment 2

The second exemplary embodiment is described with reference to FIGS. 2,3 and 4. FIG. 2 is a flowchart depicting a method of coding plural videosignals in a second exemplary embodiment of the present invention. Thereare several different points from FIG. 1. First, a work is added, i.e.input a picture, and divide it into plural portion pictures. FIG. 3shows a bit-stream data structure resulting from coding digitally theplural portion pictures. This is the same as described in the firstexemplary embodiment. FIG. 4 shows also the same operation steps as thefirst exemplary embodiment, and provides an example of data description.

On Step 21 in FIG. 2, input video signals to be coded, and on Step 22divide the video signals into plural portion pictures with a method thatdivides a picture into elements such as objects and backgrounds withinthe picture.

Regarding Step 23 to Step 26, the same operation as in FIG. 1 exceptsubstituting the portion video signals for the video signal. One videosignal is divided into plural portion video signals and composinginformation, and the coded picture data thereof are supplied in the formof bit-stream having the structure shown in FIG. 3(B).

Through these steps, one picture can be accurately transmitted, and alsothe picture can be edited with ease by re-writing the composinginformation at decoding operation.

FIG. 11 includes the following elements: input terminal 221, dividingmeans 222, picture identifier attaching means 223, composing informationpreparation means 224, first encoding means 225 and second encodingmeans 226.

Operation of the picture coding apparatus constructed as above issimilar to that of the apparatus described in FIG. 10, except fordividing the input signal into plural portion video signals in thedividing means 222 before feeding them into picture identifier attachingmeans 223 (Step 22 in FIG. 2). Therefore, picture identifier attachingmeans 223 has a portion of the video signals as an input, rather thanthe video signals-as shown with respect to FIG. 10.

Exemplary Embodiment 3

FIG. 5 is a flowchart depicting decoding and composing in the thirdexemplary embodiment. FIG. 6 illustrates a decoding and composingapparatus employing the method shown in FIG. 5. FIG. 7 illustratesschematically how the two pictures are composed. An operation of theapparatus shown in FIG. 6 is described with reference to FIGS. 5 and 7.

FIG. 6 lists the following elements: input terminal 100, separator 101,control decoder 102, video decoders 103 and 104, frame memory bank 105,composer 106, and display unit 107.

An operation of the picture decoder and composer constructed as above isdescribed hereinafter.

(1) Input received picture data and composing information to the inputterminal 100 (Step 51 in FIG. 5.)

(2) Send the composing information to the control decoder 102 using theseparator 101 via a line 108, and convert the information into a controlsignal (Steps 52, 55 and 56.)

(3) Input the coded picture data to the video decoders 103 and 104 (Step53.) Two video decoders are prepared in this exemplary embodiment inorder to make the description simple; however, arbitrary numbers ofvideo decoders can be provided.

(4) Decode the coded picture data in the video decoders 103 and 104, andreproduce different pictures, then store them in the frame memory bank105 (Steps 53 and 54.) The video decoders utilized in this exemplaryembodiment employ “inter-frame motion compensation” and “discrete cosinetransformation” that are typical functions of MPEG 1; however, the videodecoder embodying the present invention is not limited to this type.

(5) Based on a control signal sent from the control decoder 102 via aline 117, access the object reproduced pictures for composing in theframe memory bank 105, and send the subject pictures to the composer 106via a line 118.

(6) In the composer 106, compose the reproduced pictures sent via a line115 following the control signal sent via the line 118 (Step 57.)

(7) Output the composed picture on the display 107 when necessary (Step58.)

The above operation is described with reference to the specific picturesin FIG. 7. A first reproduced picture 201 has been reproduced by thevideo decoder 103. A second reproduced picture 202 has been reproducedby the video decoder 104.

The first reproduced picture 201 and the second reproduced picture 202are composed in the composer 106 into a picture 203. The control signalsent via the line 118 in FIG. 6 assigns the first picture 201 a frontview, and the second picture 202 a background.

The operation is further detailed with reference to FIG. 3 used in thefirst and second exemplary embodiments. A first coded picture data shownin FIG. 3(A) and a second coded picture data in FIG. 3(C) are composed.

The picture data 304 having time (i) is headed by a sync. signal 301followed by the identifier (ID) 302, time identifier (TR) 303, andcoding data in this sequence. The identifier (ID) and the timeidentifier (TR) are indicated in 5 bits and 16 bits respectively.

The picture data 330 having time (i+1) is also headed by a sync. signal306 followed by the identifier (ID) 307, the time identifier (TR) 329,and coded data. Because FIG. 3(A) contains coded data in a same picturefamily, all the identifiers (ID) are the same; however, because the timeidentifiers (TR) depend on display times, they take different values.

The data structure of the second coded picture shown in FIG. 3(C) is thesame that in FIG. 3(A); however, the identifiers used in FIG. 3(C) takedifferent values from those in FIG. 3(A) to distinguish themselves fromeach other.

The data shown in FIG. 3(B) are produced through packetizing andmultiplexing the picture data. The first coded picture data shown inFIG. 3(A) and the second coded picture data in FIG. 3(C) are separatedinto plural packets before being multiplexed. For instance, the picture304 having time (i) is separated into video packets 311 and 315, thepicture 328 having time (i) is separated into video packets 313 and 317,and then, they are multiplexed. Headers 310, 312, 314 and 316 areattached to respective packets. These headers include a packetidentifier that is written in 6 bits fixed-length code. Different packetidentifiers are attached in order to distinguish the first coded picturedata from the second coded picture data. The composing information isalso packetized into a composing information packet 319, and thenmultiplexed. The packet 319 also has a header to which a packetidentifier different from that of video packets is attached. In a packetidentifier list (OAT) 309 lists the packet identifiers of the composinginformation packets and the packet identifiers of the packets containingthe subject pictures to be composed.

The multiplexed data shown in FIG. 3(B) is to be received (Step 51 inFIG. 5.) By referring to the packet identifier list, the separator(demultiplexer) 101 in FIG. 6 sorts out video packets and composinginformation packets, where each packet has a packet identifier. Thenrestore the selected video packets to coded picture data, and input theminto the video decoders 103 and 104 (Step 52.)

On the other hand, the composing information packet is restored to thecomposing information and sent to the control decoder 102, where thecomposing information is analyzed and converted into control information(Steps 55, 56.) The control decoder in this exemplary embodiment is ascript interpreter, which analyzes the script of composing informationas follows:

FIG. 4 depicts the composing information 401, where composition time402, composing sequence 403, information for blending filter 404 andframe memory control information 405 are listed. The composinginformation defined as above is utilized as follows for composing apicture.

The composition time 402 indicates the time when a picture is composedwith hour, minute and second. When the time comes in accordance with thetimer of the apparatus, the picture is composed and displayed accordingto the composing sequence 403 and the information for blending filter404. The composing sequence 403 includes picture identifiers (OID), timeidentifiers (TR), depth (CO), placement (XPOS, YPOS). When thecomposition time comes, the picture designated by the picture identifierand time identifier is accessed in the frame memory bank 105 to be readout, and the picture is composed following the depth and placement ofthe relevant picture.

In this exemplary embodiment, “CO=0” indicates the deepest background ofthe picture, “CO=1” indicates a front picture next to the background“0”, and “CO=2” indicates further front picture to the layers of “CO=1”and “CO=0”. The placement indicates the picture position on thecoordinates in the displaying area. In this exemplary embodiment, “(0,0)” indicates a center of the displaying area.

The information for blending filter 404 includes a coefficient of afilter that filters boundaries of the composed picture. In thisexemplary embodiment, the coefficient of filter is 3×3. The frame memorycontrol information 405 controls the opening and securing of the framememory bank 105 in FIG. 6. In this exemplary embodiment, a picturehaving a picture identifier {0} releases the occupied memory.

The timing with which a picture is composed and displayed is describedhereinafter with reference to the composing information in FIG. 4. FIG.8 illustrates part of the timing. The X axis indicates a display time ofthe composed picture. The composing information is indicated from 513 to517. A picture having a picture identifier 2 (<OID>{2}) is indicatedfrom 501 to 505. A picture having an identifier 3 (<OID>{3}) isindicated in 506 and 507. A picture having an identifier 4 (<OID>{4}) isindicated from 508 to 512.

At the time “t5”, the pictures 501, 506, 508 and the composinginformation 513 are available, and according to the information 513, apicture is composed and displayed. When the picture 508 cannot bereceived or reproduced due to the business of the transmission line orlimited capability of the apparatus, only the pictures 501 and 506 arecomposed. At the time “t8”, the pictures 504, 511 and the composinginformation 516 are available, but the picture having the pictureidentifier 3 is not available. The information 516 in this case isdepicted in FIG. 4, and the time identifier of the picture having theidentifier 3 is indicated “5” (i.e. <OID>{3}, <TR>{5} of the composingsequence 403 in FIG. 4.) In other words, at the time “t8”, it is enoughto compose the pictures 504, 506 and 511. When a picture of which timeidentifier is designated is unavailable, a picture having a timeidentifier prior to this one can be used for composing. For instance, ifthe picture 511 having the identifier 4 and time identifier 8 is notavailable, the picture 510 replaces the picture 511 and is used forcomposing. At the time “t6” and “t7”, the same process is necessary.

The time chart in FIG. 8 represents the case where composing informationis continually received. When the composing information is notcontinually received, the composing information most recently receivedis utilized for composing until the information is updated. For example,the composing information 514, 515, and 516 are not received, theinformation 513 is kept using for composing pictures until theinformation 517 is received. In this case, the time identifier attachedto the information 513 is replaced with those attached to eachreproduced picture when composing is practiced.

The information for blending filter 404 and the frame memory controlinformation 405 are not always included in the composing information401. The picture placement information and time identifier are also notalways included in the composing sequence 403. When the time identifieris not always included, pictures to be composed can be identified withthe time identifier attached to each reproduced picture. The composinginformation can include data other than the above.

A decoding process and a composing apparatus are described with regardto pictures, the same process and apparatus can be applicable when audiosignals are composed.

Exemplary Embodiment 4

FIG. 9 is a block diagram illustrating a decoding and composingapparatus utilized in a fourth exemplary embodiment of the presentinvention. The structure and the basic operation are the same as thosein FIG. 6. An input terminal 601 is added to the structure shown in FIG.6. A remote controller or a keyboard can be used as the input terminal601. Part of the composing information is changed via the input terminal601. For instance, data of depth out of the composing sequence 403 ischanged so that the background can replace the front view.

Exemplary Embodiment 5

The coding method and decoding method described in the first, second andthird exemplary embodiments can be recorded in a recording medium. Thedata resulting from executing the methods disclosed in the first andsecond exemplary embodiments can be also recorded in a recording medium.

Industrial Applicability

When elements, such as objects in a picture, defining the picture arecoded and transmitted independently for composing each element into apicture, and also when plural video signals are coded and transmittedfor composing these signals into a new picture, the present inventionprovides the composing information that tells how to compose the pluralvideo signals. The composing information is transmitted together withthe video signals so that the information can be changed with ease atdecoding, and the new picture can be flexibly and arbitrarily composed.As a result, a noticeable advantage can be obtained such thatinteractive performance satisfying both sender and receiver can bepracticed in editing.

1. A method of coding a picture comprising the steps of: (a) inputting aplurality of video signals, each of said plurality of video signalsrepresenting an elemental portion of said picture; (b) attachingrespective picture identifiers to said plurality of video signals foridentifying said video signals; (c) outputting composing information fordefining one of said plurality of video signals by composing saidplurality of video signals, said composing information including atleast layout information and depth information for locating saidelemental portion in said picture; (d) encoding said video signal towhich at least said identifier is attached; (e) encoding said composinginformation independently from said video signals; and (f) packetizingand multiplexing said encoded video signals and said independentlyencoded composing information into respective packet signals.
 2. Anapparatus for coding a picture comprising: (a) input means for inputtinga plurality of video signals, each of said plurality of video signalsrepresenting an elemental portion of said picture; (b) pictureidentifier attaching means for attaching a respective picture identifierto said video signals for identifying thereof; (c) composing informationpreparation means for outputting composing information that is used forcomposing said plurality of video signals, said composing informationincluding at least layout information and depth information for locatingsaid elemental portion in said picture; (d) first encoding means forencoding said video signal to which at least said picture identifier isattached; and (e) second encoding means for encoding said composinginformation independently from said video signals.
 3. A method ofencoding a picture wherein a video signal is composed with a pluralityof pictures, said method comprising the steps of: (a) dividing a videosignal into a plurality of video signals, each of said plurality ofvideo signals representing a portion of said picture; (b) attaching arespective picture identifier to said plurality of video signals foridentifying said video signals; (c) outputting composing informationthat is utilized for defining said video signal by composing saidplurality of video signals, said composing information including atleast layout information and depth information for locating said videosignal in said picture; (d) encoding said video signals to which atleast said picture identifier is attached; (e) encoding said composinginformation independently from said video signals; and (f) packetizingand multiplexing said encoded video signals and said independentlyencoded composing information into respective packet signals.
 4. Apicture coding apparatus that composes a video signal having a pluralityof pictures, said apparatus comprising: (a) dividing means for dividingsaid video signal into a plurality of video signals; (b) pictureidentifier attaching means for attaching a respective picture identifierto said plurality of video signals for identifying said plurality ofvideo signals; (c) composing information preparation means foroutputting composing information to define said video signal bycomposing said plurality of video signals, said composing informationincluding at least layout information and depth information for locatingsaid plurality of video signals in said picture; (d) first encodingmeans for encoding said plurality of video signals to which at leastsaid picture identifier is attached; and (e) second encoding means forencoding said composing information independently from said videosignals.
 5. A method of decoding and composing a picture comprising thesteps of: (a) receiving a plurality of coded data representing aplurality of video signals; (b) decoding said coded data; (c) extractinga respective picture identifier attached to said coded data for saidplurality of video signals; (d) receiving independently coded composinginformation that is utilized for composing said plurality of coded data,said composing information including at least layout information anddepth information; (e) decoding said independently coded composinginformation, including said layout information; and (f) composing saidplurality of coded data based on at least said picture identifiers, saiddecoded composing information and said layout information.
 6. A picturedecoding and composing apparatus comprising: (a) receiving means forreceiving a plurality of coded data representing a plurality of videosignals; (b) decoding means for decoding said received plurality ofcoded data; (c) picture identifier extracting means for extracting arespective picture identifier attached to said coded data to be decodedfor said plurality of video signals; (d) coded composing informationreceiving means for receiving independently coded composing informationthat is utilized for composing said plurality of coded data, saidcomposing information Including at least layout information and depthinformation; (e) coded composing information decoding means for decodingsaid independently coded composing information, including said layoutinformation; and (f) composing means for composing said plurality ofcoded data based on at least said picture identifier, said decodedcomposing information and said layout information.
 7. A method ofencoding a picture according to claim 3, wherein recording of steps(a)-(f) in a recording medium is executed.